The present invention relates to a scroll compressor with two scrolls for compressible fluids.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Scroll compressors with two scrolls operate at virtually pulsation-free feeding of gaseous working fluid, e.g. air, and may find application for supercharging internal combustion engines, among other purposes. During operation of this type of compressor, a plurality of approximately crescent-shaped work chambers are enclosed in the displacement chamber or feed chamber between a spiral displacement member and two peripheral walls of the displacement chamber and move from an inlet through the displacement chamber toward the outlet, whereby the volume of the displacement chamber steadily decreases while the pressure of the working fluid correspondingly increases. An example of such a scroll compressor is disclosed in German patent document DE 33 47 081 A1. The displacement member is driven by an eccentric shaft and is held by a bearing upon the eccentric of the eccentric shaft. This bearing requires lubrication, using a lubricant, e.g. oil, contained in a lubricant chamber. To seal the lubricant chamber against the feed chamber, shaft sealing rings are typically used which are provided at the bearings of the driveshaft in a housing as well as at the bearings of the displacement member. In certain load situations, the pressure in the feed chamber can exceed the pressure in the lubricant chamber so that there is a risk that the shaft sealing rings become detached from the shaft and thus from the eccentric during operation. As a result, working fluid, e.g. air, may migrate to the lubricant side of the shaft sealing rings and escape through a lubricant recirculation line. A loss of working fluid adversely affects operation of the scroll compressor, in particular when operating at low speed.
It would be desirable and advantageous to provide an improved scroll compressor to obviate prior art shortcomings.